The aim of this study was to determine the fetal loss rate after fetal
blood sampling (FBS) in relation to the indication. In total, 1981 FB
S procedures (1878 pregnancies) were included, of which 117 were perfo
rmed for the detection of congenital infection (group 1), 1437 for the
detection of haemoglobinopathy (group 2), 233 for prenatal diagnosis
with normal ultrasound findings (group 3); 121 for rapid karyotyping i
n cases with abnormal sonographic findings (group 4) and 73 for severe
growth retardation (group 5). All the procedures were performed with
a free-hand technique under continuous ultrasound guidance. Pregnancy
losses occurring within two weeks of FBS were considered procedure-rel
ated losses. 343 pregnancies were terminated. Of the remaining 1535 co
ntinuing pregnancies, 73 (4.8 per cent) were lost, of which 39 (2.5 pe
r cent) were lost within two weeks of the procedure. The procedure-rel
ated losses were 3 in 103 (2.9 per cent), 17 in 1090 (1.6 per cent), 2
in 191 (1 per cent), 11 in 84 (13.1 per cent) and 6 in 67 (8.9 per ce
nt) in groups 1, 2, 3, 4 and 5, respectively. The differences in proce
dural loss between the five groups were highly significant: suggesting
that the method entails a much higher risk when the fetus is structur
ally abnormal, or severely growth retarded. Patients should therefore
be counselled before the procedure accordingly. (C) 1998 John Wiley &
Sons, Ltd.